splitter: use more lightweight split.js for sidebar splitter

yarn.lock

@@ -3530,11 +3530,6 @@ locate-path@^5.0.0:
   dependencies:
     p-locate "^4.1.0"
 
-lodash.throttle@^4.1.1:
-  version "4.1.1"
-  resolved "https://registry.yarnpkg.com/lodash.throttle/-/lodash.throttle-4.1.1.tgz#c23e91b710242ac70c37f1e1cda9274cc39bf2f4"
-  integrity sha1-wj6RtxAkKscMN/HhzaknTMOb8vQ=
-
 lodash@^4.0.0, lodash@^4.17.10, lodash@^4.17.11, lodash@^4.17.14, lodash@^4.17.15, lodash@~4.17.12:
   version "4.17.15"
   resolved "https://registry.yarnpkg.com/lodash/-/lodash-4.17.15.tgz#b447f6670a0455bbfeedd11392eff330ea097548"
@@ -5410,13 +5405,6 @@ spdy@^4.0.1:
     select-hose "^2.0.0"
     spdy-transport "^3.0.0"
 
-split-me@^1.2.2:
-  version "1.2.2"
-  resolved "https://registry.yarnpkg.com/split-me/-/split-me-1.2.2.tgz#64c1641f455d61662e7674cca4896f4ee4e72792"
-  integrity sha512-wZF3TUNVn/DGoLfMlg3wFbYmh+vhLDSZ6fcIVcVH6xuf/v9Es4aXcynYvEiyO71zniv4TqsUEhQkwPJ1xnz5FQ==
-  dependencies:
-    lodash.throttle "^4.1.1"
-
 split-string@^3.0.1, split-string@^3.0.2:
   version "3.1.0"
   resolved "https://registry.yarnpkg.com/split-string/-/split-string-3.1.0.tgz#7cb09dda3a86585705c64b39a6466038682e8fe2"
@@ -5424,6 +5412,11 @@ split-string@^3.0.1, split-string@^3.0.2:
   dependencies:
     extend-shallow "^3.0.0"
 
+split.js@^1.6.2:
+  version "1.6.2"
+  resolved "https://registry.yarnpkg.com/split.js/-/split.js-1.6.2.tgz#b8c63aeef2b15d84a003ead09e7def6ad166bb40"
+  integrity sha512-72C7zcQePzlmWqPOKkB2Ro0sUmnWSx+qEWXjLJKk6Qp4jAkFRz1hJgJb+ay6ZQyz/Aw9r8N/PZiCEKbPVpFoDQ==
+
 sprintf-js@^1.1.2:
   version "1.1.2"
   resolved "https://registry.yarnpkg.com/sprintf-js/-/sprintf-js-1.1.2.tgz#da1765262bf8c0f571749f2ad6c26300207ae673"